Insulin Like Growth Factor 2 mRNA Binding Protein 1 (IGF2BP1)

IMP1 contains 6 characteristic RNA-binding modules, including 2 N-terminal RRM domains and 4 central and C-terminal KH domains. It shares 59% amino acid identity with IMP2 and IMP3, 95% identity with chicken zipcode-binding protein, and 99% identity with mouse Crdbp. Immunocytochemical analysis of cultured cells showed a dynamic subcellular localization for IMP1 that was dependent upon the cell type, the degree of cell differentiation, and exposure of the cells to serum factors that differ between newborn and fetal calf serum. However, analysis of mouse embryos showed that expression of all 3 Imp transcripts peaked at embryonic day 12.5 and declined toward birth. RNA dot blot analysis detected moderate IMP1 expression in placenta and in all human fetal tissues of mixed first-trimester age examined.